2019 Mazda3 revealed: New model challenges Toyota Corolla

The new generation Mazda3 - the second most popular small car in Australia behind the Toyota Corolla - has been unveiled at the Los Angeles motor show ahead of a showroom arrival in mid-2019.

Sleeker, longer and wider than the previous hatch and sedan, the new model is a new design and promises class-leading tech, including forward cross-traffic alert and driver fatigue cameras that monitor eye movement.

Familiar 2.0 and 2.5-litre four-cylinders are expected to carry over, to be joined by a new 140kW petrol engine with groundbreaking technology that promises diesel-like fuel economy and lower pollution.

The SkyActiv X 2.0-litre uses a tiny supercharger - Mazda calls it an "air-supply device" - to push extra air into the engine's cylinders. Rather than increasing power like a conventional supercharger, its job is to make the fuel mixture thinner.

This enables the engine to run an ultra-high compression ratio to burn fuel more efficiently. Test drives have demonstrated real-world efficiency gains of between 15 and 17 per cent.

The engine reportedly does not need spark plugs but Mazda has fitted them for added refinement low in the rev range.

This tech is likely to be available on dearer versions of the Mazda3.

There is greater differentiation between the sedan and hatch, which now share only bonnet and windscreen. Previously, most panels and doors were shared.

The fresh look for both variants is aimed at invigorating the small-car class, which has experienced a sales slump since the surge of SUVs.

He said the small-car class was far from dead. "There's still a lot of demand for small cars," he says.

Mazda is yet to release pricing and model details. However it has disclosed that all new Mazda3s would come with a driver's knee airbag, bringing the tally to seven.

Traffic jam assistance - which inches the car forward in traffic when activated - will be available on dearer versions for the first time.

The Mazda3 will have Apple CarPlay and Android Auto as standard.

The new Mazda3 will also be one of the first models from the brand to have Apple CarPlay and Android Auto as standard - smartphone mirroring has been a $500 dealer-fit accessory on most Mazdas sold over the past five years.

Mazda also claims to have made further improvements in sound insulation. Previous Mazdas have been raucous compared to their peers because sound-deadening material was often the first to be jettisoned when trying to save weight.

However the company insists it has found new ways to make its cars quiet without bringing a weight penalty.

Only the bonnet and windscreen body panels carry-over from the hatch to the sedan version.

Mazda says it has created a special floor underlay that "leaves space between the body and carpeting" and also reduced the number of gaps in the carpeting "wherever possible to significantly enhance sound insulation".

The new Mazda3 also has "sound-absorbing" roof lining and floor mats that "effectively suppress high-frequency noise".